\begin{tikzpicture}[>=Stealth, scale=0.5,
    every node/.style={fill=white, inner sep=1pt},
]
    \draw [->] (-7, 0)   -- (5, 0) node[below=0.2em] {$x$};
    \draw [->] (0, -5.5) -- (0, 7) node[left=0.2em]  {$y$};
    \draw (0, 0) node [below right=0.3em] {\small $O$};
    \foreach \x in {-3, -2, -1, 1, 2, 3, 4} {
        \draw (\x, 0.2) -- (\x, 0) node [below] {\small $\x$};
    }
    \foreach \x in {-4, ..., -6} {
        \draw (\x, 0.2) -- (\x, 0);
    }
    \foreach \y in {-3, -2, -1, 1, 2, 3} {
        \draw (0, \y) -- (-0.2, \y) node [left] {\small $\y$};
    }
    \foreach \y in {-4, -5, 4, 5} {
        \draw (0, \y) -- (-0.2, \y);
    }

    \draw[domain=-7:4.2,  samples=5] plot (\x, {2*\x/3 + 4}) (-4, 2) node [above, rotate=30] {$y = \frac{2}{3}x + 4$};
    \draw[domain=-7:4.2,  samples=5] plot (\x, {2*\x/3}) (4, 2) node [below, rotate=30] {$y = \frac{2}{3}x$};

    \foreach \x in {3, 1, -2.2, -5} {
        \coordinate (a) at (\x, 2*\x/3 + 4);
        \coordinate (b) at (\x, 2*\x/3);
        \draw [dashed] (a) -- (b);
        \draw[decorate,decoration={brace,mirror,amplitude=0.2cm}] (a) -- (b)
                node [pos=0.5, left=0.5em] {\small $4$};
    }
\end{tikzpicture}

